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[Yang Youseok <1784203@xxxxxxxxxxxxxxxxxx>]

Public bug reported:

Description
===========
Currently, VM provisioning is possible even in a hypervisor where the number of physical cores does not satisfy the number of vcpus. I found core_filters does not care physical cores at all.

VM having vcpus which is more than physical cores keep context switch,
and result in bad neighbor for other VMs.

The number of VCPUs more than physical cores definitely make no sense,
so imo core_filters should restrict the scheduling.

Steps to reproduce
==================
* Make flavor which has many vcpus (e.g. 32 cores)
* Provision VM having that flavor in the hypervisor which do not have sufficient physical cores (e.g. 16 physical cores)

Expected result
===============
Scheduling failed emitting "available host not found"

Actual result
=============
VM normally provisioned

Environment
===========
1. Exact version of OpenStack you are running. See the following
  list for all releases: http://docs.openstack.org/releases/

   newton-eol, but master looks same.

2. Which hypervisor did you use?
   libvirt + kvm

2. Which storage type did you use?
   ceph

3. Which networking type did you use?
   neutron with linux bridge

** Affects: nova
     Importance: Undecided
         Status: New

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https://bugs.launchpad.net/bugs/1784203

Title:
  core_filter in scheduler does not care about physical cores

Status in OpenStack Compute (nova):
  New

Bug description:
  Description
  ===========
  Currently, VM provisioning is possible even in a hypervisor where the number of physical cores does not satisfy the number of vcpus. I found core_filters does not care physical cores at all.

  VM having vcpus which is more than physical cores keep context switch,
  and result in bad neighbor for other VMs.

  The number of VCPUs more than physical cores definitely make no sense,
  so imo core_filters should restrict the scheduling.

  Steps to reproduce
  ==================
  * Make flavor which has many vcpus (e.g. 32 cores)
  * Provision VM having that flavor in the hypervisor which do not have sufficient physical cores (e.g. 16 physical cores)

  Expected result
  ===============
  Scheduling failed emitting "available host not found"

  Actual result
  =============
  VM normally provisioned

  Environment
  ===========
  1. Exact version of OpenStack you are running. See the following
    list for all releases: http://docs.openstack.org/releases/

     newton-eol, but master looks same.

  2. Which hypervisor did you use?
     libvirt + kvm

  2. Which storage type did you use?
     ceph

  3. Which networking type did you use?
     neutron with linux bridge

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